全文获取类型
收费全文 | 1868篇 |
免费 | 64篇 |
出版年
2023年 | 8篇 |
2020年 | 24篇 |
2019年 | 39篇 |
2018年 | 53篇 |
2017年 | 65篇 |
2016年 | 68篇 |
2015年 | 38篇 |
2014年 | 44篇 |
2013年 | 496篇 |
2012年 | 46篇 |
2011年 | 61篇 |
2010年 | 56篇 |
2009年 | 55篇 |
2008年 | 50篇 |
2007年 | 30篇 |
2006年 | 43篇 |
2005年 | 46篇 |
2004年 | 43篇 |
2003年 | 36篇 |
2002年 | 35篇 |
2001年 | 29篇 |
2000年 | 32篇 |
1999年 | 18篇 |
1998年 | 39篇 |
1997年 | 31篇 |
1996年 | 22篇 |
1995年 | 18篇 |
1994年 | 27篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 14篇 |
1987年 | 19篇 |
1986年 | 21篇 |
1985年 | 17篇 |
1984年 | 25篇 |
1983年 | 20篇 |
1982年 | 25篇 |
1981年 | 12篇 |
1980年 | 16篇 |
1979年 | 18篇 |
1978年 | 8篇 |
1977年 | 19篇 |
1976年 | 14篇 |
1975年 | 11篇 |
1974年 | 11篇 |
1972年 | 9篇 |
1968年 | 7篇 |
排序方式: 共有1932条查询结果,搜索用时 15 毫秒
81.
Invasive cordgrass (Spartina spp.) in south‐eastern Australia induces island formation,salt marsh development,and carbon storage
下载免费PDF全文
![点击此处可从《Geographical Research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
David M. Kennedy Teresa Konlechner Elisa Zavadil Michela Mariani Vanessa Wong Daniel Ierodiaconou Peter Macreadie 《Geographical Research》2018,56(1):80-91
Invasive vegetation species can lead to major changes in the geomorphology of coastal systems. Within temperate estuaries in the southern hemisphere, especially Australia and New Zealand, the cordgrass Spartina spp. has become established. These species are highly invasive, and their prolific growth leads to the development of supratidal environments in formerly intertidal and subtidal environments. Here, we quantified the impact of Spartina invasion on the geomorphology and sequestration capacity of carbon in the sediments of Anderson Inlet, Victoria, Australia. Spartina was first introduced to the area in the 1930s to aid in land reclamation and control coastal erosion associated with coastal development. We found that Spartina now dominates the intertidal areas of the Inlet and promotes accretion (18 mm/year) causing the formation of over 108 ha of supratidal islands over the past 100 years. These newly formed islands are calculated to potentially contain over 5.5 million tonnes of CO2 equivalent carbon. Future management of the inlet and other Spartina‐dominated environments within Australian presents a dilemma for resource managers; on the one hand, Spartina is highly invasive and can outcompete native tidal marshes, thereby warranting its eradication, but on the other hand it is likely more resilient to rising sea levels and has the potential for carbon sequestration. Whether or not the potential advantages outweigh the significant habitat change that is anticipated, any management strategies will likely require additional research into costs and benefits of all ecosystem services provided by Spartina including in relation to nutrient cycling, shoreline stabilisation, and biodiversity as well as in response to the longevity of carbon found within the sediments. 相似文献
82.
83.
84.
85.
86.
87.
88.
A Spanish Man‐o‐War in New Zealand? The 1864 wreck of Grafton and its lessons for pre‐Cook shipwreck claims
下载免费PDF全文
![点击此处可从《International Journal of Nautical Archaeology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Peter Petchey Rachael Egerton William Boyd 《International Journal of Nautical Archaeology》2015,44(2):362-370
This paper considers the 1864 wreck of Grafton in the Auckland Islands, and its implications for wreck analysis and pre‐Cook exploration claims. The captain of Grafton, Thomas Musgrave, stated that the schooner was built from the wreck of a Spanish man‐o‐war, and archaeological analysis of the wreck found that the timbers are a tropical South American species, and had possibly been reused. The implications of this are clear; it is possible that timbers that originated in pre‐Cook (1769) ships lie in New Zealand, but without a full understanding of the historical and archaeological context of any such timbers, including their reuse in later ships, it is not possible to claim proof of pre‐Cook European exploration of New Zealand. 相似文献
89.
AbstractThe loss of agricultural land and its implications have been of great concern in the last decade. By undertaking a spatial analysis of the appropriation of agricultural land for urban use with an overlay of population and urban data, a focus on the consequences of certain regulations on the dynamics of land-use change is explored. This is achieved by integration of data inventories of agricultural land use for Portugal, and linking this information with CORINE Land Cover data as to assess change in the Algarve. An integrated assessment of agricultural land loss follows, undermined by the consequences of urban sprawl. In this sense, this paper expands on the currently existing decrees which provide support to sustainable development in the region while providing a qualitative assessment of future roles based on ethical values and economic efficiency and offering a feasible framework for policy-makers regarding the trends of urban/agricultural dichotomy in a planning and decision-making context. 相似文献
90.